The subject matter disclosed herein relates to an optical enhancing device, such as a telescopic observation sighting device or individual shoulder (or hand-fired) firearms sighting device (telescopic sight herein). Embodiments according to the subject matter disclosed herein may also be used with any optical enhancing device containing adjusters, such as a microscope, telescope, etc. For purposes of illustration, it will be assumed herein that the optical enhancing device is a telescopic firearms sight.
A telescopic sight, typically used to aim a firearm, is usually mounted on the firearm. An adjustment knob on a telescopic sight is typically used for changing a setting of an adjuster, for example, elevation, crossrange (also referred to as windage herein), or parallax, of the telescopic sight. Parameters such as elevation, crossrange, and parallax, may be painstakingly set in order that the projectile fired from the firearm hit a specific target at the intended point of impact (POI). Once set for a particular projectile/ambient condition/distance combination, the adjustment setting preferably remains unchanged unless ambient conditions or the distance changes or until after a shot is fired at the target, whereas the adjustments may be changed for another set of conditions.
Existing telescopic sighting systems for civilian, law enforcement, and military firearms typically utilize three types of adjustment knobs. The first type of adjustment knob has a cover cap that must be removed to make a sight setting adjustment. The second type of adjustment knob has no cover cap and is permanently exposed and allowed to rotate freely. The third type of knob is a locking knob in which the lock must be released prior making an adjustment.
Around the circumference or at the base of all three types of knobs are numerals and index marks to indicate the rotational setting of the knob with respect to a fixed datum mark. To adjust the knob of the telescopic sight so that the projectile impacts the target requires an operator to make multiple practice shots and become intimately familiar with the specific projectile trajectory profile under various ambient conditions and distance combinations. During the intended use, whether it is hunting, competition, military use, or police tactical use, the operator must visually check the reference marks against the datum mark and modify the adjustments based on the knowledge gained through practice at the same or similar distance and ambient conditions such that the bullet point of impact is at the desired place on the target. It is almost impossible for the operator to be intimately familiar with the projectile trajectory for the infinite number of bullet, velocity, distance, slope, temperature, and weather condition combinations that exist in the field. Under these conditions, the operator must make a “best guess” and make adjustments accordingly. Presently all adjustment values are gauged from the reference marks and datum marks for each adjustment knob. In some circumstances, such as military or tactical applications in which the telescopic sight is used in the dark, the operator cannot visually check the external telescopic sight setting scale, which necessitates some sort of internal scale that is possibly illuminated.